There exist various electronic apparatuses provided with a connection jack (DC jack) to which a connection plug is (DC plug) is connected, for example, a recording/reproducing apparatus performing recording and reproduction of images and audio, an acoustic apparatus performing output of audio and so on, an imaging apparatus performing imaging of images and video, a network communication apparatus performing various communication, and information processing apparatuses such as a personal computer and a PDA (Personal Digital Assistant) (for example, see JP-A-2006-278118 (Patent Document 1)).
The connection jack includes a center electrode and an earth electrode arranged at an outer periphery of the center electrode, and respective electrodes are connected to a capacitor and an electronic circuit arranged inside the electronic apparatus.
On the other hand, the connection plug is connected to an AC adapter connected to a power supply plug and the power supply plug is connected to commercial power, thereby supplying DC current converted by the AC adapter to the connection plug. The connection plug includes a center terminal to be connected to the center electrode of the connection jack and an earth terminal arranged at an outer peripheral side of the center terminal and connected to the earth electrode of the connection jack.
When the connection plug is connected to the connection jack, DC current is supplied from the connection plug to the capacitor to be charged, and respective units of the electronic circuit are driven by rated current.